package cn.bj.yu.pc;

/**
 * @author 周宇
 * @create 2020-08-10 15:02
 * 线程之间的通信问题：生产者和消费者问题  等待唤醒 通知唤醒
 * 线程交替执行 A B 操作同一个变量 num =0
 * A num+1
 * B num-1
 */
public class ProducerConsumer_synchronized {
    public static void main(String[] args) {
        Data data = new Data();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "A").start();

        new Thread(() -> {
            for (int i = 0; i <= 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "B").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "C").start();

        new Thread(() -> {
            for (int i = 0; i <= 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }, "D").start();
    }
}

//判断等待、业务、通知
class Data {  //数字 ，资源
    private int number = 0;

    //+1
    public synchronized void increment() throws InterruptedException {
        while (number != 0) {
            //等待
            this.wait();
        }
        // 干活
        number++;
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        // 通知
        this.notifyAll();
    }

    //-1
    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
            //等待
            this.wait();
        }
        // 干活
        number--;
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        // 通知
        this.notifyAll();
    }
}